Evening primrose is easy to grow: it grows often taller than 5 feet. Evening primrose is a night bloomer: the flowers with strong sweet fragrance open up in the evening and close during the day during the months of June to October. The oblong-shaped, about an inch long fruits of evening primrose contain numerous tiny reddish seeds.

Evening primrose seeds or standardized oil preparations are uniquely rich in a fatty acid called gamma-linolenic acid (GLA) which has been found to be helpful for a wide range of conditions from arthritis to premenstrual syndrome (PMS). Almost half of women suffer from PMS, and an Australian study shows that eighty-five percent of women reported that they had tried treatments for PMS, and many reported having tried multiple treatments. In Europe, especially in England, evening primrose oil is considered as an excellent medicine for PMS.